The present invention pertains to parallel to serial (P/S) converters for receiving digital information in parallel form and transmitting it in serial form, and particularly to P/S converters wherein information contained in sets of parallel-form control bits asynchronously instructs the converter to serialize and transmit other information contained in sets of parallel-form data bits.
In some digital computer systems such as the NTDS (Navy Tactical Data System) the output of a system computer equipment comprises data words and sets of control bits, all of which are in parallel form, wherein each data output may occur at an unspecified time and the presence or absence of a data word at a given time is indicated by an instruction contained in the output control bits at that time. If the parallel data outputs must be converted into serial form, such as when NTDS parallel outputs are to be coupled into the channels of the High Speed Data Switching System (HSDS), which operates on serialized information, there exists a need for a P/S converter which can determine the times at which the equipment has a data output. In addition, a P/S converter coupling the outputs of an NTDS equipment to a channel of the HSDS must be capable of very rapid operation, since it may receive data words in parallel form at a rate in excess of 125 kilowords per second from the equipment and transmit serialized data words to the HSDS at a rate in excess of 10 megabits per second.